| 摘要 |
The invention concerns a tuneable optical filter (10) comprising: a moveable filter plate (20) and an associated optical region (30) for filtering an input radiation beam (40a) to provide corresponding filtered output radiation (40b), the optical region (30) has spatially varying filtration properties. Piezoelectric actuating elements (70a to 70d) are provided for moving the filter plate (20) and its associated optical region (30) relative to the beam (40a) for selecting a portion of the optical region (30) for use in filtering the beam (40a) and thereby tuning the filter (10), the actuating elements (70a to 70d) are operable when driven by electrical signals to repetitively engage or be in repetitively slidable contact and thereby impart a lateral force to a surface of the filter plate (20) for moving the optical region (30) relative to the beam (40) in at least one dimension. Repetitive engagement or repetitively slidable contact of the actuating elements (70a to 70d) is capable of providing the filter(10) with at least one of reduced backlash and finer adjustment resolution compared to known tuneable optical filters, the filter (10) is especially suitable for use in optical communication systems where there arises a need for occasional system reconfiguration involving retuning optical filters of the system.
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